PSI - Issue 23

Available online at www.sciencedirect.com

ScienceDirect

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000 – 000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 23 (2019) 469–474

© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers A study of 3D surface topography of the aluminum alloy 7475-T7351 after advanced machining and its material and mechanical properties were investigated in situ herein the scanning electron microscope TESCAN MIRA 3, equipped with a brand new combined tensile fixture MT1000 (NewTec, France). Advanced characterizations of material structures and electron backscattered diffraction mapping (EBSD) of selected chemical elements were made, as well as the energy dispersive X-ray analyses of the surface and distributions of the material inclusions. Some very thin cross-sections of the material have been produced by the focus ion beam technique also. The tensile tests confirmed that the cracks nucleated at the interfaces of brittle particles and metal material matrix. Consequently, the cracks spread under the increasing tensile loading and the samples were broken finally before reaching the standard tensile strength limits even. The fatigue results displayed an evident dispersion of the data, but the mechanism of fracture was similar. The surfaces topographies that have been made under selected cutting conditions by face milling operation have not proved to have any decisive impact on the fatigue properties. On contrary, a very evident decohesion between the alumina matrix and brittle inclusions have been observed frequently affecting the strength of the material. The main conclusion is that the phases the complex Al 7 Cu 2 Fe and Al-Cr-Fe-Cu-Si intermetallic inclusions have the crucial effect on the tensile mechanical and fatigue properties of the material, suppressing the expected effect of machining and surface topography. 1 9 The Authors. Published by Elsevier B.V. is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) r-review under responsibility of th scientific committe of the IC MSMF organizers. Keywords: surface topography, inclusions, fatigue, alumin alloy, tensile loading 9th International Conference on Materials Structure and Micromechanics of Fracture A Study of Crack Initiation Mechanism in the Aluminum Alloy 7475-T7351 when Tensile Loading Petra Ohnišťová a* , Mirosla v Píška a , Jiří Dluhoš b , Jana Horníková c , Pavel Šandera c , Martin Petrenec a a Brno University of Technology, Faculty of Mechanical Engineering, IMT, Technická 2896/2, 616 69 Brno, Czech Republic b TESCAN ORSAY HOLDING a.s., Libušina tř. 8 63/21, Brno-Kohoutovice, 623 00 Brno, Czech Republic c Brno University of Technology, Faculty of Mechanical Engineering, Institute of Physics, Technická 2896/2, 616 69 Brno, Czech Republic Abstract

* Corresponding author. Tel.: +420-541-142-555. E-mail address: petra.ohnistova@vutbr.cz

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers.

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers 10.1016/j.prostr.2020.01.131